Useful Debugging Tips - SFU-MARS/ros2

Logging trick

The following saves stdout to a log file while still having the log display in terminal:

ros2 launch <package> <launch file> | tee <log file>
- e.g. ros2 launch nav2_bringup tb3_simulation_launch.py | tee tb3_bringup_debug.log
This can be useful for closely inspecting the logs, or to copy content from the logs

Print transformations
- ros2 run tf2_ros tf2_echo laser_link map
Visualize transformations in real time
- ros2 run rqt_tf_tree rqt_tf_tree (need to install it first)
Visualize transformations once
- ros2 run tf2_tools view_frames

List parameters
- ros2 launch <package> <launch file> -s
More detailed outputs for debugging
- ros2 launch <package> <launch file> -d -a

It can be helpful to run a new node by itself outside of any launch file first. Parameters and topic mapping can be set from the commandline:
- ros2 run <package> <executable> --ros-args -p some_param:=some_value -p other_param:=other_value -r old_topic:=new_topic -r other_old_topic:=other_new_topic
Interact with parameters from commandline
- ros2 param list
- ros2 param get <node> <parameter>
- ros2 param set <node> <parameter> <value>
  - Use parameter callback to allow parameter setting while node is running.